Zein solution and coating composition



., \vomtions or, coatings prepared-in accordanceevvith Patented Dec. 26,1939 V I UNlTEDISTATES PATENT OFFICE zEm SOLUTION AND .coa'rnvo I ICOMOSITION ColemanyChicago, lllguassignor to The Zein Corporation ofAmerica, a corporation of Delaware No Drawing. Original applicationSeptember 21,

1939. Serial No. 295,919. Divided and this application October 11, 1939,Serial No. 298,986

I I I I 3 Claims. (01. 134-12) I I r This invention relates toixnprovements in 'sub-" the presentinvention' may separate and becomestantially anhydrous'solutions and coating "com I solid; however, onheating again to temperatures positions of zeinand-to methods of,preparing of from about 45 to 70 F., a re-solution is the same, whilethe-presentdnvention ap-x afiected, either without stirring or withslight I 5 plieableto the production oi. solutions and coat '1 stirring,and: the solutionsand coatings return to 5 ingconipositions of otherprolamins, it isparticutheirnor'malform at the re-heating temperatures.larly'jfdirected to securing substantially an- IIThestablenon-separating solutions and coat- I'f" hydrous fsolut'ionsandjcoatingfcompositions of; Ting; compositions prepared in accordancewith the 'zein with controlled solutionand gelling their "i presentinvention may be controlled as to their *aetei'isticsp"lzeizr beingdifferentiated 'froirr'oth' "gelling characteristics, as hereinafter setforth, 0 .prola.mins'-by its'unusualgelling ten encie's.and-"maybesloweelling or substantially non- ;T'hissapplicationiisialdivisipn orzmy rior {ico gelling? with j'slight tendency toincrease in visjnding a'fpplication Serial Nor- 1295919; filed Sep''cosity; than-muothicken or=become heavier in 21, 1939; i body; and inmanyinstances they exhibit vprac- I he solutions,and coatingscompositiosof'imy tically no' tendency to thicken or to gell over p esent in 'ntlon, are characterized by the, factpractical periodsoi time in the-orderof about 3 thattheyi contain either-no 'a'dded'.water,. qr only. .toabout filmonths. By virtue of these novel slight 'amounts ofvvater 'notin excess of] stable chara'cteristics,the solutions and coatings andare, the fore; ubstazi'tially anof my invention arenot llmitedtouseimmediately Q or'within short periods of time after preparation Thezeinufse'd lnaccordance with my invention as is '-'genera1ly the casewith the prior art solumay; bethe commercial" z ein? which contains a.tions' and coating compositions. The solutions 1 small-ypercentage; OfhmOiStllIG'EthGE-i order of and'coating compositions of the presentinvention {aboutfi about 81%,'preferab1y;ahout=8% ,;-and is generallyremain :stable and reasonably constant 35 obtained in the t'rade inpowdered formgoi it intheir-characteristics during the periods necesmaybeaf'specially treatedisubstantially anhydrous sary for transportationand distribution, either zein. ,llnlilthe iollovvingfdescription'[bf myginin bulk or in packages, or for storage for reaerrnjfjziei tocommercial Qsonable'periods of time, and hence their field of Iapplicability is greatly increased. u less ther'wise speciii' 'fmaccordance with the present invention, I v 1 5 designated? #1 j. havefound that'solutions and coatings of zein :Innthespri0r, art zeini'coatijng compositions; having. the desired non-separating, controlled wwater has been included .toza-gsubstantialiextent,-gelling-*or-non-gelling' characteristics may be se- ;it,; being?considered, thatathelsolubility char-,, curediby asuitable balancebetween the hydroacteristics of zein required the inclusion otj- -subcarbon, constituents g-or radicals present in the 35 stantlproportions'oilwateriinorganic solvent solvent orv solvent mixtures andthe .polar con- Eor" xaniplggasstated in the WalshetaLPatent stituentsor radicals present therein, thepres- "No; 1,966,604, the additionof"w:a, ter is necessary ence of a, certain proportion of carbon-bondedsince'fthe love-molecular weight alcohols, alcoholhydroxyl radicals I,being required to secure -ethers 'and*ltlcohol derivatives are notefiective solvent action. The presence of a'hydroxyl group 40aloneinmaklng solution'sof z'ein.-

. "-1; in a primary, alcohol'radical -CH2OH, appears pIn' accordancewith the present invention Ijj to be particularly helpful in securingsuch achave 'foundsthat non-separating, stable liquidtion, Thepresence'of' an excessive proportion of coating -con positionsptcontrolled :gellingch'a hydroxylradicals or of polar radicals including,5, ac'teris'tfics, either. slow gelling, oiysubstantially vsomehydrcnryl radicals causes or. accelerates in gelli g, gelling tendenciesin the zein solution or coating.

Polar d ca l s suchas .-O- (ether oxygen),

II id or cooperate with' Ql-Iinsecurin the neces-' d' li' i .t .l. sij5?" nfii 1 fb ityi he s e (in turjes" (if-80 F." and below and do notseparate eve whichterrn I' include solvent rriiiitures in the *1 whencooled to teinperatures of 501to '70=*F; and a :present case) forsolvent action'," and in excess 1 somewhat l belowr when cooled: even totern-. produce-the'conditions enhancing g-elling'. *Whileperaturesasziovras-10 above,zero or 'tolzero; =insolutions,absence'of'gelling or slow gelling or thickening};is:'-jdesirable,- in the preparation of separation-f the zein. The sameis the case in the presence of excessively long or large hydrocarbonradicals; e. g. C4 and higher alkyl radicals. Cyclic hydrocarbonradicals, however, behave as lower alkyl radicals; Thus, as will appearhereinafter, the benzfyfi'adicalacts as if it wereintermediateb'etween'the methyl and ethyl radicals.

cals and hydrocarbon .or non-polarradical's in--- the solvent may besecured-by the use of :a: suit 13 able individual; compoundwhich-inhernthehas the neeessaryv balance, or by; an; admixture of.compounds whichf-areindividually not-balanced 1 1a h -mi ers a ddisperse or dissolve in of the solvent;

to. secure. proper r, which individually may This is consistent with thepolar characteristics -01 aryl-alkyl radicals as compared f with alkyl-The desired balance of polar-constituent exterior ofthe's'olvate-complex, which may then the remaining constituents 'Therpro'portionof polar radicals to-hydrocarbon or non-polar-radicals whichI have found to: be desirable lieswithima range which extends. betweenthelimits -,of,abs olute methanol on the one-hand, having,53% hydroxyland 47%-- hydro.--.-. carbon,-and. absolute ethanol on the other hand I4 also, these solventsmay be .usedwithvarious, prohaving 37% hydroxyland ,-B3% hydrocarbon.

This range is approximate and may vary somewhatdepending on jthesolvent; or [solvent mixture used. The limits of this range are," how-.

ever, indicative: of gelling characteristics on the one hand and ofinsolubillty'onthe other a'nd,.

therefore; provides aclose andadequate guide to enable the operator; bysimple experimentation. to dete'nnine therequired balance of-polajr andhydrocarbon radicals to orient solution .of: zein in any solvent ormixture ofsolvents of a}, character herein set-forth. Thus absolutemetli- 1 anal has decided solvent action, but has excessive gellingtendencies, as has/also ethylenefglycol,

whichv has an even higher proportion of, --QH Glycerol, also higher inthan has methanol. -OI-I,thanmethanol, shows no appreciable solventaction on zein, a behavior which is prob,-

' ably related to its high surface tension; On'the other hand, absoluteethanol, isopropanoL-andhigher alcohols have no-apparent solvent action.

It is, of course, obvious that certain solvents or mixtures of solventshaving a balance of polar is possible, by simple experimentation, todeter mine readil that particular balanced solvent or micellesbythehydroxylated const tuents of the mixture, ij'jwith I: oriehtatioin of'thef "hydrocarbon "radicals" of the hydroxylated compo'undto the In'these examples and" in "all other eitarriples vents oftheseapplications. include diethylene glycol, triethylene glycol,propylene glycol; dia -ce tone alcohol, benzyl alcohol, cyclohcxanol andfurfiu'yl alcohol, as well .as ,tetrahydroiurfuryl alcohol and the like:These "solvents individual- 1y, ormixtures thereof, are capable ofdissolving zein to produce solutions or coating compositions iw iv' areab e a s sepm q d e trolled to be slow gel-ling} on" substantiallynongelllngr over practical periods of; time; iminany cases overfromabout'3 to'abo'ut 6 months. In the case-ordiacet-on'e alcoholandcyelohexa'nol, fora-exampl z J-lverysssmall -.proportions of water, 7:to ;-,-3;%.,, :or :of-amethanol or glycol -,may be incorporatedtherewith, to form zeinsolutions or reduced viscosities.

' fiirfur'yl and" tetrahydrofurfurylalcohol, for ex- 'v ni s arate new*e cals (+0 H; or -OH and may-be regarded as if it were intermediatebetween=the ratios for methanol and ethanol. I have found any of the'above' -balanced solvents orinixtures oi them may used- ;in" or added Tto other solvents orsolvent mixtures-wotherwise. balanced :orapproximately;balanced, such. additions being ire-.- guently desirable,,Thus, benzylzalcohol aids in securing a; bright. clear mm. ;In 1general,

portions .of ethanol, glycol or. the like, providing he ar 1 f xvldbthsrf ar group t 'Inithe"foliowingexamples when? I refer to anhydrousl denatured alcohol I have reference to the "commercial anhydrousdenatured'alcohol of the following formulafi;; 1 H Per cent h r izt'fiwt s. weight.

indicates parts by Example '1 17 10 parts of zein are mixed with 40parts of a solvent mixture containing 84% of 95% alcohol and 16% oidiethylene glycol.

v The mixture is stirred and on the application of heat in the order ofabout 85 to 95 F. for about 5 minutes,

a-clear, non-separating, substantially non-gelling stable solution ofthe zein is formed.

v Exan pZe Z 10, parts 01 zein are. mixed with 20 parts of asoivent'mixture containing 50% of benzyl-"alcohol and 50% of 95%alcohol. On stirring and cooled to about 130 to 140 F. and the 95%alwith the application of heat in the order of about 108 to 112 F. a.non-separating, substantially non-gelling stable solution of the zein inthe solvent mixture is obtained in about to 8 5 minutes.

Example 3 parts of zein are mixed with parts of a solvent.mixture.containing of benzyl alcohol and 50% 01 anhydrous'denaturedalcohol.

On stirring and with the applicatio'n ofheat in the order of about toF;, a non-separatsubstannae-ny non-gelling Stable separatingandsubstantially non-gelling.

the zei in he solvent mixture f =i"ob tained :in

"about 5-toi8 minutes.

new

.10 ori in slow gielli'ng' solution s obtained n hat a to 1'2 "minutes.

1 wiltin Jot tel tale one.

I of propylene glycol in a suitable vessel. On stirring. andwith theapplication of heatin the order V tionisobtained ingabout5E0 i v Example6 7 tion is obtained-in about 10 .to 12 minutes.

a A w 7 10 parts of zein are mixed with 20 parts of diethyleneglycolmonoethyletherand 30 parts of diacetone alcohol in a suitablevessel. On stirring and with'the application of heat in' the order 5 ofabout 135 to 145 F., a stable, slow-gelling" solution isobtainedinzabout 5' to 10 minutes;

Example 8 I 10 parts of zein'are mix ed'with. 20..partso if 1diethyleneglycol monoethyl'ether,,12rparts1zo triethylene glycol and 8,parts ben-zyl. alcohol:- in

- a suitable vessel. .Onstirring, and with the-fappligcation ofheatinthe order of;abou t" .-to 1 30? FL," a stable slow. gellingsolution i b glycol to a temperature --in theord'er of: about 190 to 195F. to form a solution. The solution is permitted to cool to about toF.., atwhich temperature the anhydrous denatured alcohol is added. Theresulting solution is non-separating and substantially non-gelling.

Example 10 v i 10 parts of zein are mixed of solvent mixture containing50% of diacetone al- 001101 and 50% of, 95% alcohol.,Inpractice the zeinis mixed with the diacetone alcohol and heated to about 190 to 200 F.for about 8 to 12' 5 minutes to eflect solution. The solution is thenand methanol. 1 containing. 5 to 45%. of toluol are excellent sol-;vents fonzein, and have retarded and in some cohol is then added. Theresulting solution is non-separating and substantially non-gelling.

Example 11 10 parts of zein are mixed with 200 parts of a solventmixture containing 40% of propylene glycol and 60% of 95% alcohol. Inpractice, the zein is heated in the propylene glycol to about to F. toeffect solution. The solution is then cooled to about 130 F. and the 95alcohol is then added. The resulting solution is nonv Example 12 I 10parts of zein aremixed with 20 parts of ylene glycol and 20 parts ofdiethylene glycol. fO'n stirring and withthe application'of heat in theorder'oi about to Ff, a clear, nonseparating, substantially non -gellingstable solution' bf 'the-aein injthe solvent mixture is obtained 12minutes.

." feit mple 13 10 parts o f ze in aremixed with 30. parts of s pa ts-.diethylene glycol monoethyl ether and. 15 parts,

,F a' stablc-kSlow-gelling solution is obtainedin i 1 ""10pa'rts of zeinar'e 'mixed with 70 parts of 10 parts of 'zeinr are mixed-with 20 partsof 5 diethylene glycol *monoethyl ether and 20" parts of benzyl alcoholin a suitable vessel. On' stirring and with the application of heatinthe orderof about 110 to 120 F., a stable, slow-gelling solupropylene"glycol and '30 parts of glycerine in a suitable vessel. Onstirring andwith the applicationjo'f heat in the order of about 140 to 160 wFJ,astable; slow-gelling solution is obtained in about 8 .to l2 'minutes.

plioation ofgl 'eatin the order of about 160 to 'f '17 0 F.,'a stable,slow-gelling solution is obtained about 5 to 10 minutes.

.Examplew 10 parts of zein are mixed with 32 parts of triethylene glycoland 8 parts of glycerine in a suit- -:a;ble-ves'sel;; On stirring andwith the application of heat. in the order of about 120,to 130 F., a

10 to 12 minutes.

,Solvent mixtures of nongelling or controlled gelling characteristicsmay be produced by mix- Ang miscible compounds having a'deficiency ofydroxyllorjpolar radicals with compounds havncefor an excess thereof tosecure the I lance of polar and hydrocarbon "radialsii'in the resultingmixtures. An extreme example of the production of such solvents is theadmixture of toluene (a non-solvent for zein) Mixtures of methanol andtoluol cases relatively slow-gelling tendencies. The

preferred range is 35 to 45% toluol.

as used in these examples and elsewhere throughout the specification, Ime'an' solutions of zein in solvent mixtures which have retarded gellingtendencies with respect to the gelling time of solutions of zein in theconstituent of the mix- :stable, slow-gelling solutionis obtained inabout ture of solvents having a tendency to form a gelling zeinsolution.

Examplev 17 10 parts of zein are mixed with parts of a mixtureconsisting of about 55% of methanoland about of toluol. On stirring andwith the application oi heat in the order of about 100 to 105 l., anon-separating, stable solutionjof the; zein in the'solvent mixturehaving greatly retarded gelling tendencies is obtainedr he'at iri-theforder of about 90' to 110 F., a non vent mixture having-retardedsgeliing tendencie *is-obtained.

-.heafted .in the cyclohexanolffto aboutiflgof to Emmple 18 10 arts or zein are madam-24' parts of v anhydrous isopropyl alcohol and 6 parts ofC. P. glycerine in a suitable vessel. 0n stirring and with theapplication of heat in'the'o'rder of about '115 to 125F.,-a--non-'separating, slowgelling, stable solution of the zein in thesolvent mixture is obtained.

' f w I Example}? 10 parts ofzein are mixed with 30 parts of ethyleneglycol monomethyl etherj and 10" parts offt'oluol in a suitable've's'sel. On"stir1"in"g"=and with theapplication of heat'inthe or'dei'of about E: '140 to145 F.,' a non-separating-stable solution of the--zein in: the solvent mixture is. obtained stirring andwith the'application 0 separating; Es'ttible solution-of the zein; in: thersol:

Separating, slow-gellin I, in the solvent mixtur '75 to 85 F., anon-separating, substantially sawgelling, stable solution of the mm inthe solvent mixture is obtained.

Example 24 I 1 10 parts of zein are mixed with 44 parts'of 95% alcoholand 6 parts of dioxan in a suitable vessel. The mixture is stirred andon the ap- V plication'ofheat in -tlie" order"of-=*to 85 F., a

Stable? p rating slow senmg sollltion 6r the zein" is produced. 1

"Emmi M25 1 0 pans of zein at,ammmsataatr a a solvent mixture containing50% of ethylene glycol monomethyl ether and 50% of anhydrousdenaturedalcohol. Qn stirring and with the application of heat "in theorder of to F., a.

stable, non-separating".slow gelling solution is obtained.

10 parts o f zein arernixed witli 40 parts'of a j solvent mixturecontaining 84% anhydrous de-' red-alcohol and 16 of-ethyleneslycol, Thextu e is st rred. a dtopgthe. apbl tiqe. 0; h a

the order offa boutf9oito F., a clear, ndnstable solution jof, zein ,5mixed with 30;- p rts Q 1, anhydrous isopropyhalcohohandQO parts;

of linseed fatty acids. ,In. practice, the jzeln is' I v 2009,11 toeffect solution. "I'l1e solution is then cooled to about 'F.',J-a'na'the other ingredients are added. The solution formed is stable andnon-gelling.

Anhydrous or substantially anhydrous solvents may be prepared from thealiphatic-alcohols hav-- ing from? to 4 carbon atoms-byadding. theretohydroxylated or polar compounds having higher g ratios of V or. polargroup s-1 (including CQ, -NHz', or f-QOI-D' than ethanol to secure thedesired baian'ce'd relationsfbetween" polar and non-polar groups. Thesimplest'rnono and polyhydric alcoholsare particularly useful inthisconnection, these being methanol; glycol";

and glycerol. The following examples areillus-Q vtrative of'zeinsolutions prepared with such-solvent mixtures in accordance withv myinvention.

. Example- 22 I '19 parts 01- z'ein are mixed with 4o parts'pf solventmixture containing 86% of 95 alcohol 5 and 14% of ethylene glycol. The?mixture is:

stirredand on the application 0f-"heat in' the or- Example 23 10 partsor zeinare mixed'with 40 parts of a{ solvent mixture containing 89% of95% alcohol and-11% 'oi' dichlorethyl. 'etli'eri On'stirring and'with'the application of heatin the order oi about u j d na m xtur Walcohols 'must Bec' balanced relations between groups are secureTneisolvencs a d o'lv'e'nt zein der'ot about 9Q=to=95 F;-,-aclear-pnon-separating, of Q the DmpgmqtgTgpQv slow-gelling,stablesolutionofthe zeinin-the-solventmixtureiisiormedrr.f-i-

obtained. I

used in lieu is also apparent, .in ac.

invention that-the ro set forth above; as'r'wejll as ether. solvents" orsol-. ventxmixtures whichzg will? be apparent-from the foregoing, and,the resulthjig,:.=.solj1tionsiprepared injaccordance awith theipresentinvention are; siib- T lstantially anhydrous;:- containing not rno re;,.than

- It isapp'arentthat ethylenegdichloridefitetra-a T chlorethyleneandzithe -;like.;-zmays of di-chlorethyl ether in the-above examples. It t1 5 of added. waterand, preferably, ub tantiau i s. e p bnq ibna of navae m sibl are .thus limited inlcrdertofsecur. the-{desiredisolu 4 .765

tion characteristics and control of ell tui-bs the'j b alan ce a:tee-sol ent fendm duce p g I cceierate geiling; as v the c aract r-a"::the' z'ein fihn depos1ted solution? Possible expnnauonstr thebeliavior.v of water 'm ay be i'nade bntnebasumnae it acts as a highly polar-.'constituentwhen presnt in solution'fin excess,'-=thatitJtendsitogcausegsolvation or hydration-of the zein,gand,-its:tendencyto cause cases, as set forth in my application Serial -N l 58,2l,5,. andin. all other; instances 'is but, one

constituent of a mixt ure itwill.;be appar nt-that 1 th s v ntst ptfeiredwi presentnv9nii e il Cific t instances) I herein 1' "mean havingjinsufileie thereof and introduce "excessivegellingor insoluance" withmy invention,'I*am thus"enabled to prepare substantially non aqu'e ous:zein solutions and coatingcompositions' which'contain nojadded water,"or only slight amountsthereof, 'riot in "excess"of"% and, preferably;less. "By"virtl'ie of this low'added watefcontent,the'ileldfofapplicabi'lity of theeo'ating compositionsan'd solutions inaccordance 'with' m'y "invention is {materially widened beyond that oft'he aqueouscoating' compositions of the"pr'iorfz einjart. In additionthe films deposited from my vcoating"compositions and solutions have,none of the' serlous'drawbacks as to brittleness, lack oflusterand'glo'ss 1 and 'blooming'and blushing tendencies ofthe filmsdeposited from the'aqueou's solutions'or coating compositions oftheprior art. i

Certain anhydrous'or substantially anhydrous compounds 'or mixtures ofcompounds in accordbalance of polar and""hydrocarbonradicalsapproaching" that of ethanol and bordering the desired range,hav'e'be'en found to be excellent solv vents for zein. Solutions orcoating compositions formed by "the aid. of these solvents are stableagainst separation of the zein and produce solutions in which thegelling tendencies can be more readily controlled than in the case ofsolutions orcoating compositions formed by the aid of these solvents andsubstantial amounts of water as in the prior art. Of the solvents,meniion may be made of ethylene glycol monomethyl ether, diethylenevglycol monomethyl ether, ethylene glycolmonoethyl ether, diethyleneglycol monoethyl ether and like alcohol-ether solvents or mixturesthereof.

The quantity of anhydrous or substantially anhydrous solvents ormixtures of solvents-necessary to prepare the desired solutions orcoating compositions in accordance with my invention Seat n be d an emin mum ipeimissibi FMPO'PtiOH ay 1 n uee iinea 11,.

entally injeachinstarice' a l'ld 'ifi" rriany i h y."ab e e va id o sa'fi enection with solventsor solvent mixtures; as'used p A "ter i a; the:v ffsolventpr solvent mixture tddisturbthe balance bilityj' and havinginnoease-more than 5%" Water, f By the use of -"anhydrous orsubstantially an- 'liydro'us solvents-or 'solventfmixturesfin accOrdancewith my invention; characterized having a may vary rather widely fromabout 2 tog-20 or more and, preferably from about 2 to about 9 or moreparts by weight of the solvent to 1 part by weight of the zein. In mostinstances, 3 to 5 parts by weight of the solvent to one part by Weightof the zein has been found sufiicient to dissolve the zein and form thedesired stable solutions-or-eoating compositions. The viscosity andgelli-ng; tendencies.- of sitheisolutions f0! coating ompositionsprepared :in-accordancewith my in- Y @01 a at least-in. partdependent-on the H sine uhfiu, ll properties, particularly rih'ated bfbeing able to givefupftl'ieir' s01- r solvents readily when applied to?any surquiclr'lyl'and read ly form tough, flexible, tack h tdt n nerallytrans a e f i when 'e'taining some] solvent. The} films deect ca use-a yn eialg hch P pen texti1es,.;wood, wa e-2 1 -,e i e. ka1 e e e e n ie tvim ybe us deithrp r eo iin-comb mea nd emes an ih -1 k a a ,Thecharacteristics oiithecoating compositions in" accordance with, myinvention,, and hence not the ultimate; iilmsgf ormed therefrom; can be:alteredat will and as-desiredbythe inclusion' 'of vdiluents, modifiers,plasticizers, resins, cellulose derivatives, filler-sand the like all as'setforth in my application Serial No.-'295,'919

Iclaim:

-- 1. A substantially non-aqueous-liquid' coating a compositioncomprising-a solution oi zeinin a substantially anhydrous mixture ofsolvents comprising an organic compound having a proportion of polar tonon-polar radicals which lies within a range extending between-thelimits of the proportion of polar to non-polar radicals of methanol andthe proportion of polar to nonpolar radicals of ethanol and an organiccompound.

having a proportion of polar to non-polarrradicals which is greater thanthe proportion of polar to non-polar radicals of methanol, said solventsand said composition containing not in excess 01 5% of added water, andsaid composition being stable against separation of the Zein at tempera-1 of methanol and the proportion of polar to nonpolar radicals ofethanol and. an organic com: pound having a proportion of polar tonon-polar radicals which is greater than the proportion of polar tonon-polar radicals of methanol, said solvents and said compositioncontaining not in excess of.5% of added water, and said compositionbeing stable against separation of the zein at temperatures of 70F. andbeing-relatively nongelling. 1

3. A substantially non-aqueous composition comprising a solution 012a:prolamin in a substantially anhydrous mixture oiisolvents having aproportion of polar to non-polar.radicals which lies within a rangeextending between the limits of the proportion of polarfto non-polarradicals of methanol and the proportion of polar to non-polar radicalsof ethanol, said mixture of solvents comprising an organic compound-having a proportion'of polar to non-polar radicals which lies within arange-extending between the limits of the proportion oi -polar tonon-polar radicals of methanol and the proportion oipolar to'non-polarradicals of, ethanol and an organic compound having a proportion ofvpolar. to nonev polar radicals whichis greater than the proporf tion ofpolar to nonj-polar radicals of methanol,

said solvents and said composition containing not in excess of 5%ofadded water, and said'comwater, and-said composition .beingstableagainst position 'b'ein'g stable against separation of the prolamln attemperatures of 70F. and being relatively non-gelling. I

'4. A substantIaIIy non-aqueous com 1 position comprising a, solution ofzein in asunstantially anhydrous mixture of solvents having aproportionof polarto non-polar radicals which lies' within a range extendingbetween the limits of the proportion of polartoinon-polar radicals of"methanol and the proportion of polar to'nonpolar radicals of ethanol,said mixture of solvents comprising an organic compound having aproportion of polar tonon-polar radicalsfwhich lies within arrangeextending between the limits of the proportion of polar to non-polarradicals of methanol and the proportion of polar to, nonpolar radicalsofethanol and a polyhydric alcohol of the class consisting oi ethyleneglycol and glycerine, said solvents and said composition containing notin excess of 5% of added water, and said composition being stableagainst separation of the zein at temperatures of 70 B. and beingrelatively non-gelling.

5. A substantially. non-aqueous liquid coating composition comprising asolution of zein in a substantially anhydrous mixture of solventshavliquid coating,

to non-polar radicals of ethanol, said mixture of solvents comprisingbenzyl alcohol and ethylene glycol, said solvents and said compositioncontaming notin excess:ot,5%' of added water, and

said composition being stable against separation of the zein attemperatures 01 70 F. and being relatively non-gelling.

v x 6. 'A' substantially non-aqueous liquid coating compositioncomprising a solution of'zein in asubstantially anhydrous mixture ofsolvents having a proportion ofpolar .to non-polar radicals which lieswithin a range extending'between the limits of the DIOPOIMQILOI' polarto non-polar radicals of methanol and the proportion of polar to Pl-.991?! radicals, of ethanol, saicl mixture of solvents comprising:propylene glycol; and 'g lycer ine, said solvents and said compositioncontaining not in excess of 5% of added water, and said compositionbeingstableagainst separation of the zein at' ternpe're'ltur'es of"TilF; and being relative- 7. A' substantially noneaqueous, liquid coatingcomposition.comririslngaflsolutionoi zein ina i allv. an s l sm tu l Qso ventsfha r which lies within ;a range extending between the jlimlmibfithe proportion of polar'to non-polar ethylene glycol, saidsolvents and saidcomposi-t ing-a; proportionbipolar-Itonon polarradicals tion: containing not in Hexcessof 5%. oi addejd separation 01'the zein at temperatures of 70F.

and which is relatively non-gelling, comprising mixing an hydroxyorganic compound having-a proportion'oi' polar to non-polar radicalswhich lies within a range extending between the limits of the proportionof polar to non-polar radicals of methanol and the proportion of polartO'l'lOll-IDO- lar radicals oi" ethanol 'with an organic com-1 poundhaving a proportion of polar tonon-polar radicals which is greaterthan'the proportion of polar to non-polar radicals of methanol to form asolvent mixture having a proportion of polar to non-polar'radicals whichlies within a rangeextending between the limits of the, proportion ofpolar to non-polar radicals of methanol andthe proportion of polar tononpolar radicals of ethanol and dissolving zein in'said solventmixtureto form said solution, said solvent mixture containing not in excess o'f5% 'of added water.

ROY COLEMANL

